准分子激光角膜切削术的角膜地形图对比研究

目的:分析准分子激光角膜切削术(photorefractivekeratectomy,PRK)前后角膜表面的形态特征及术后偏心情况。方法:应用计算机辅助的角膜地形图仪对75例(148眼)PRK前后角膜地形图进行检测。结果:术前角膜地形图以蝴蝶结形为多(72.3％);术后78.4％为圆形或钥匙孔形、半圆形和蝶形为19.6％,中央岛形占2.0％。PRK对散光的一次最大矫正量为-1.75D,切削中心偏位是最佳矫正视力下降,复视和屈光度回退的重要原因。结论:角膜地形图的检查可准确显示PRK术后角膜形态的细微变化,有利于手术效果的提高。

CORNEAL TOPOGRAPHIC CONTRAST STUDY BEFORE AND AFTER EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY

Objective: To analyze the morphological features of corneal surface before and after photorefractive keratectomy(PRK) and the decentralization of the ablation. Method: Corneal topography was examined on 148 eyes of 75 cases with myopia by computer-assisted photokeratography before and after PRK. Results: The corneal topography of most examined eyes(72. 3%) was bow tie pattern before PRK. But after PRK. the corneal topography of the ablated regions was mainly round or keyhole - like (78. 4%) bow tie pattern and semicircular were 19. 6% and 2. 0% was central island. The largest corrected diopter of astigmatism was - 1. 75D one time. The decentralization of the ablation site was an important cause of the decrease of the best corrected visual acuity, diplopia and dioptric regression. Conclusion: The examination on the corneal topography before and after PRK can display accurately the changes of the corneal surface morphology and also can improve curative effect.